Ernesto Hernandez

Rubberized concrete (RuC), which incorporates recycled tire rubber aggregates in the matrix, offers a viable solution for managing waste tire disposal. Although adding rubber aggregates reduces the compressive strength of concrete, research suggests that in specific applications, such as flexure-controlled members, this adverse effect can be minimized. However, detailed studies on the flexural performance of reinforced RuC members remain limited. This paper presents a comprehensive study to assess the flexural performance of RuC beams, providing detailed measurements of concrete strains, steel strains, neutral axis depth, and crack widths. The experimental program tested 12 reinforced concrete beams with varying rubber content (0%, 10%, and 20% of total aggregate volume), tension reinforcement ratios (

The psychological mechanisms through which occupational stress impacts quality of life remain underexplored in shift-working healthcare professionals, a population exposed to unique stressors such as circadian disruption, high cognitive demands, and irregular work schedules. This study examined whether executive self-regulation mediates the relationship between perceived stress and quality of life in a sample of 82 shift-working healthcare professionals. Participants completed validated self-report measures, including the Perceived Stress Scale (PSS-4), Executive Skills Questionnaire–Revised (ESQ-R), and Quality of Life Scale (QOLS). Mediation analysis using 5126 bias-corrected bootstrapped samples revealed that perceived stress significantly predicted self-regulation difficulties, which in turn were associated with diminished quality of life. Self-regulation demonstrated an indirect-only mediation effect in both directions, though the forward path (stress → self-regulation → QOL) showed a stronger effect (indirect effect = −0.79; 95% CI: −1.63, −0.17), compared to the reverse path (QOL → self-regulation → stress; indirect effect = −0.04; 95% CI: −0.08, −0.01). Unsupervised K-means clustering identified three distinct behavioral clusters: resilient, low-strain, and high-strain, providing further support for personalized targeted interventions. These findings highlight self-regulation as a central mechanism through which stress affects quality of life and underscore the need for interventions that strengthen executive functioning in shift-based healthcare settings.